36 ROYAL SOCIETY OF CANADA 
5. Subdermal triradiates.—Sagittal; somewhat similar in shape to 
the subgastral triradiates but with shorter lateral rays and a slightly 
shorter basal ray. The lateral rays are inclined out of the plane of the 
basal ray and viewing the spicule from the front their extremities curve 
slightly away from the basal ray. Lateral rays about ‘078 by ‘006 mm. 
in size, basal ray averaging ‘170 mm. long and ‘006 mm. thick at mid- 
length. The spicule, as regards its position in the wall, is opposite to 
the subgastral triradiates, its lateral rays lying parallel to the dermal 
surface whilst the basal ray reaches some distance toward the gastral 
surface. 
6. Dermal oxea.—Occurring in layers in the dermal cortex nearly 
parallel with the long axis of the sponge but with a slight obliquity 
outward and upward. Tapering gradually to a sharp point at each end, 
straight or very slightly curved, averaging ‘822 mm. in length with a 
thickness at midlength of ‘013 mm. 
7. Linear spicules —vVery slender, scattered among the cortical oxea 
at right angles to and projecting beyond the dermal surface; about ‘098 
mm. long and ‘002 mm. thick. 
Locality—Strait of Belle Isle, off Norman’s Light, 60 fathoms, 
rocky bottom, A. M. Rodger, 9th of April, 1892, two specimens and the 
upper end of a third. 
This species is named after Mr. A. M. Rodger, through whose efforts 
this interesting and valuable collection of sponges have, in a great 
measure, been secured. 
AMPHORISCUS THOMPSONI. (Sp. nov.) 
(Plate III, figs. 8, 8a-7.) 
Sponge solitary, erect, nearly cylindrical, broadest at midheight, 
without an oscular fringe. Wall thin, about ‘15 mm. through, inclosing 
a comparatively wide gastral cavity. Surface even, echinated by stout, 
projecting oxea. Texture firm. The larger of two specimens is slightly 
over 1 cent. long and at midlength is about 1°5 mm. broad, tapering a 
little toward each extremity. 
Skeleton.—The skeleton consists of gastral quadriradiate and tri- 
radiate, of subgastral triradiate, of subdermal triradiate and of dermal 
triradiate spicules with large oxea and small linear spicules projecting 
beyond the dermal surface. 
1. Gastral quadriradiates—Stout, with sharply pointed rays. The 
apical ray, straight, about ‘085 mm. long and ‘006 mm. thick at mid- 

